1. Field of the Invention
This invention relates to external medications, more specifically to external medications having excellent skin occlusive properties.
2. Description of the Prior Art
It has been known that outdoor winter air conditions, domestic kitchen work, miscellaneous house work and the like tend to cause crazing, chapping or the like, especially, in the skin of women and to aggravate housewives eczema, keratodermia tylodes palmaris progressiva, etc. It has also been known that atopic dermatitis and xerosis senilis aggravate in winter. Although various creams, ointments and the like have been placed on the market in order to improve and treat such xerodermia, creams or ointments having remarkable effects do not appear to have been provided yet. For various skin diseases to which non-steroidal antiinflammatory drugs or steroidal antiinflammatory drugs are applied, creams, ointments and the like containing a variety of drugs have been developed and placed on the market for many years. The effects of these external medications are however still weak and under the circumstances, their therapeutic results are very poor. As to steroid-containing external medications, the steroids which are medicinally-effective components have themselves poor percutaneous absorption and under the circumstances, they can exhibit therapeutic effects only by occlusive dressing technique (ODT).
On the other hand, two causes have generally been accepted as principal causes for xerodermia of the skin, one being loss of lipids from the skin surface and the other loss of water in the corneum. For these reasons, a preparation form capable of suppressing transpiration of water from the skin surface, that is, a preparation form having water tightness has been considered to be highly effective in easing the skin xerodermia. Preparations containing an oily component, e.g., vaseline or the like as a base have hence been used widely. In spite of their high occlusive effects against water diffusion of skin, they are accompanied by such drawbacks that they are sticky and prone to fouling and they cannot be used with comfort. Especially, preparations formed of oil in water (o/w) type creams as bases are accompanied by such shortcomings that their therapeutic effects relying upon the creamy bases are reduced because their emulsifier are hydrophilic and their water tightness are lowered and they are hence easily washed off with water.
Another therapeutic method has also been known conventionally, in which a thin plastic film is applied on a medical preparation coated on the skin in order to promote the percutaneous absorption of its medicine. However, this therapeutic method is not used too much routinely these days because the application of such a film is cumbersome.